I know people are curious to see MAC header results, so here they are.

I just got back from the dyno. I dynoed SAE:

SAE 284rwhp / 318rwtq I love the TQ numbers

with the mods below. My a/f was right at 12.8 until 4000 RPM - 5800 RPM where it dropped to 12.0. So there is some more power in it yet. Also consider that I am still running through a single CAT. I bet if I get it leaned back to 13.0 and removed the cat, I would easily be over 290 rwhp / 320 rwtq.

Here is a link to the dyno sheet. I love the TQ below 4500 RPM. The dyno sheet is STD numbers, but you can see the correction factor to SAE was only 1.01 so all the numbers just need to be divided by 1.01 to get SAE numbers.

Mac Midlength Headers, Carsound Cat, Hooker Catback, K&N FIPK

I made an Excel graph of a good running stock '97 M6 vs my dyno results.

Here it is. Please right click, save as:
Stock vs MAC Header Chart

Dan

 

Nice numbers.

You didn't get a before-header dyno did you? That would be interesting to see.

 

Great numbers for your mods. You don't happen to have numbers before the headers?

 

Thanks.

Unfortunately, no. Most of the stock M6 LT1's run about 250-255rwhp / 285 rwtq stock though.

I really like my low end TQ. It definately follows header theory that a smaller diameter tube (1 5/8") helps to keep exhaust speeds high at low RPM's. Since that helps scavenging, the TQ numbers look great down low. I mean, my rwtq doesn't drop below 310 even at 1800 RPM. It can make me suffer up top, but I think I would need quite a bit more HP before the 1 5/8" primaries start to choke my engine.

I'm not sure what LT's dyno at with similar mods, but keep in mind that I have a cat in my system, which LT's typically don't, so I'd probably gain a good 5 rwhp easy if I took it out.

I can't wait to put a cam in. If I can keep the TQ that I have down low, and extend the TQ curve to a higher RPM with the cam, the HP numbers will shoot up like crazy. I'm glad I bought the MACs.

Oh yeah, thanks to Motown Muscle for setting up the dyno day.

Dan

 

I rode in stereos car today and it ran awesome. It actually feels faster than the dyno numbers indicate. I was impressed. I went inside the shop today and they had the hooker aerochamber muff for 60 bucks. I am def gonna swap my lm for the hooker.
nice meeting you today Dan. Dan is a top notch guy.
Brandon

 

Thanks Brandon. It was fun meeting you today. That LT1 of yours is sweet!

Dan

 

Nice numbers, Dan!
Here's mine: http://www.jonaadland.com/NewPics3/Baseline.JPG

That's with FLP's, 3.5" Mufflex/Borla XR-1, No Cats & "Lousy" G2 CAI

Quote:

It definately follows header theory that a smaller diameter tube (1 5/8") helps to keep exaust speeds high at low RPM's. Since that helps scavenging, the TQ numbers look great down low.

I've never put much faith in that theory on these cars. My dyno above doesn't support it either. Of course both systems would need to be tested on the same car for an accurate comparison....just food for thought.

 

Looks good Jon!

I think the cat is hurting me about 5 hp or so, plus running at 12.0 A/F above 4000 RPM doesn't help either.

Once I get that worked out, I bet I'll be at about 290 rwhp/322 rwtq.

Dan

 

Dan!! Nice numbers! I'd be interested to see what it puts down with an off road pipe and some tuning. That's pretty impressive.

 

My #'s are in sig, I have 1.6 rr's though, but I also have an A4 which hurts dyno #'s. I put out 318 rwhp STD just to compare. Oh yeah, my LT's didn't hurt lowend torque at all, if anything they helped it. I still have too much torque to know what to do with. Oh yeah, people say the dyno I went to reads 10-15ft lbs low on the torque side...

 

Nice #'s man. I just got my car dyno'ed also with my Hooker LT's and cutout open. I only put out 283rwhp and 319rwtq but i got a lot more in the car. I was running very rich. I was at mid 11 a/f most of the rpm range and up top i was high to mid 10 a/f.

 

Speed demon

Thanks for the numbers to compare with. You don't have a cat right?

I think 1.6 RR's are supposed to get you at least 10-15 rwhp, so take that off and you are at 287-292 rwhp. Through an A4, that is great!

Yeah, today was a dyno day, and the LS1 guys said that the dyno was reading low today, but I think they were just acting a little tough. A guy that dynoed 375 SAE before supposedly only dynoed 360 SAE today.

I'm not questioning my numbers though. They seem to be right on what I thought they would be. I was thinking I might reach 290, and without the cat, I'm pretty sure I'd be there.

Dan

 

Get that baby leaned out to 13 a/f and you are going to be rockin!

BTW, my 284/318 numbers are SAE corrected.

Dan

 

No cats, through a hooker catback with an 18" bullet in the I-pipe.

 

How's that bullet muffler working for you? That's exactly what I was thinking of doing. Does the exhaust smell strong? Any popping/raspiness? I'm also wondering how much louder that is than the cat.

Dan